Revelation 16:3
The SECOND angel poured out his vial upon the sea; and it became as the blood of a dead man: and every living soul died in the sea.
Revelation 8:8-9
And the second angel sounded, and a great mountain as it were all on fire was cast into the sea; and the third part of the sea became blood:
Revelation 11:6
during their prophecy they have power to prevent any rain descending from heaven: their power extends over waters to turn them to blood, and to smite the earth with what plagues they please.
Revelation 10:2
he held in his hand a little book open: his right foot was upon the sea, and his left foot on the land.
Revelation 13:1
Then I saw a beast rise up out of the sea, having seven heads, and ten horns; upon his horns were ten crowns, and upon his heads the name of blasphemy.